Efficient Electromagnetic Wave Absorption Research Articles

Single-source-precursor derived SiOC ceramics with in-situ formed CNTs and core–shell structured CoSi@C nanoparticles towards excellent electromagnetic wave absorption properties

In this work, novel CNTs/CoSi/SiOC nanocomposite ceramics with<em> in-situ </em>formed multi-walled carbon nanotubes (CNTs) and core-shell structured CoSi@C nanoparticles were successfully prepared <em>via</em> a single-source-precursor derived ceramic approach. The polymeric precursor characterization as well as phase evolution, microstructure and electromagnetic wave (EMW) absorption properties of the ceramics was investigated in detail. The results show that the <em>in-situ</em> formed CNTs and magnetic CoSi@C nanoparticles provide a synergistic effect on both dielectric loss and magnetic loss, leading to outstanding EMW absorption properties of the ceramics annealed at only 1100 °C, as follows: 1) For the Co feeding 6.25 wt.%, the minimum reflection loss (RLmin) is -53.1 dB and the effective absorption bandwidth (EAB) is 4.96 GHz (7.12-12.08 GHz) with a ceramic-paraffin hybrid sample thickness of 3.10 mm, achieving the full X-band coverage; 2) For the Co feeding 9.09 wt.%, the RLmin value of -66.4 dB and the EAB value of 3.04 GHz (8.4-11.44 GHz) were achieved with a thickness of only 2.27 mm. Therefore, the present CNTs/CoSi/SiOC nanocomposite ceramics have potential applications for thin, lightweight and efficient EMW absorption in harsh environments.

Ultra-lightweight and multifunctional ionic liquid-modified graphene/polyimide aerogels for efficient electromagnetic wave absorption

Ultra-lightweight and multifunctional ionic liquid-modified graphene/polyimide aerogels for efficient electromagnetic wave absorption

Designing flower-like MOFs-derived N-doped carbon nanotubes encapsulated magnetic NiCo composites with multi-heterointerfaces for efficient electromagnetic wave absorption

In order to acquire exceptional electromagnetic wave absorption properties, the microstructure design and component modification of composites are essential. Metal-organic frameworks (MOFs), due to the unique metal–organic crystalline coordination, tunable morphology, high surface area, and well-defined pores, have been regarded as promising electromagnetic wave absorption materials precursors. However, the inadequate contact abilities between adjacent MOFs nanoparticles endow it with undesirable electromagnetic wave dissipation capacity at a low filler loading, which is a great challenge to break size effect of nanoparticles to achieve efficient absorption. Herein, NiCo-MOFs derived N-doped carbon nanotubes encapsulated with NiCo nanoparticles anchored on flowers-like composites (denoted as NCNT/NiCo/C) were successfully prepared through facile hydrothermal method followed by thermal chemical vapor deposition with melamine-assisted catalyst. By controlling the Ni/Co ratio in precursor, the tunable morphology and microstructure of MOFs are achieved. Most importantly, the derived N-doped carbon nanotubes tightly connect the adjacent nanosheets to construct the special 3D interconnected conductive network, which effectively accelerates the charge transfer and improves the conduction loss. And notably, the NCNT/NiCo/C composite delivers excellent electromagnetic wave absorption performance with minimum reflection loss of −66.1 dB and wide effective absorption bandwidth up to 4.64 GHz when the Ni/Co ratio is 1:1. This work provides a novel method for the preparation of morphology controllable MOFs-derived composites and realizes high-performance electromagnetic wave absorption properties.

Carbon nanotube arrays@cobalt hybrids derived from metal-organic framework ZIF-67 for enhanced electromagnetic wave absorption

Highly efficient electromagnetic wave (EMW) absorption materials with excellent thermal management are urgently required to solve the problem of electromagnetic pollution. Herein, bead-curtain-like carbon nanotube arrays@cobalt (CNT As@Co) hybrids are designed to enhance the EMW absorption performance by using CNT As templates. After the in-situ growth of ZIF-67, CNT As@Co hybrids are successively fabricated by thermal pyrolysis of CNT As@ZIF-67 at high annealing temperature. Owing to the unique three-dimensional (3D) bead-curtain-like microstructures, the CNT As@Co hybrid pyrolyzed at 500 °C (CNT As@Co-500) with an ultra-low filler loading of 2 wt% exhibits optimal EMW absorption properties. The minimum reflection loss (RLmin) is −36.86 dB at a thickness of 5.5 mm, and the effective absorption bandwidth (RL < −10 dB) reaches as broad as 5.78 GHz with a thickness of 2.5 mm. In addition, CNT As@Co hybrids possess superior thermal conductivity (9.25 W m−1 K−1) among most similar CNT-based composites, which is conducive to the rapid dissipation of thermal energy converted from electromagnetic energy. This work provides a new paradigm for designing high-performance 3D EMW absorbers with multifunctionality in electronic devices.

Enhanced microwave absorption of superlattice C-CuS/MXene composites with rich heterogeneous interfaces and conductive network synergies

Improving interfacial polarization and enhancing conductive losses have become two important ways to achieve high electromagnetic wave absorption performance in dielectric materials. However, relying on a single loss mechanism to attain efficient electromagnetic wave absorption performance is challenging. Consequently, a composite material that leverages multiple loss mechanisms must be devised. Here, we introduce a superlattice C-CuS and MXene (Ti3C2Tx) composite that facilitates excellent interfacial polarization and conductive loss capability simultaneously. The superlattice structure harbors an abundance of heterogeneous interfaces on the molecular level, resulting in significant improvements in polarization losses. The introduction of MXene facilitates the formation of conductive networks and enhances the conductive loss, thus improving the electromagnetic wave absorption performance. As a result, C-CuS/MXene shows an ultra-efficient electromagnetic wave absorption performance with effective absorption bandwidth of 5.12 GHz at only 1.6 mm. This work has inspired the rational design of micro/nanostructures for a new generation of electromagnetic wave absorbing materials.

Ordered Heterostructured Aerogel with Broadband Electromagnetic Wave Absorption Based on Mesoscopic Magnetic Superposition Enhancement.

Demand for lightweight and efficient electromagnetic wave (EW) absorbers continues to increase with technological advances in highly integrated electronics and military applications. Although MXene-based EW absorbers have been extensively developed, more efficient electromagnetic coupling and thinner thickness are still essential. Recently, ordered heterogeneous materials have emerged as a novel design concept to address the bottleneck faced by current material development. Herein, an ordered heterostructured engineering to assemble Ti3 CNTx MXenes/Aramid nanofibers/FeCo@SiO2 nanobundles (FS) aerogel (AMFS-O) is proposed, where the commonly disordered magnetic composition is transformed to ordered FS arrays that provide more powerful magnetic loss capacity. Experiments and simulations reveal that the anisotropy magnetic networks enhance the response to the magnetic field vector of EW, which effectively improves the impedance matching and makes the reflection loss (RL) peaks shift to lower frequencies, leading to the thinner matching thickness. Furthermore, the temperature stability and excellent compressibility of AMFS-O expand functionalized applications. The synthesized AMFS-O achieves full-wave absorption in X and Ku-band (8.2-18.0GHz) at 3.0mm with a RLmin of -41dB and a low density of 0.008gcm-3 . These results suggest that ordered heterostructured engineering is an effective strategy for designing high-performance multifunctional EW absorbers.

Correction to “Covalent Bonding of MXene/Reduced Graphene Oxide Composites for Efficient Electromagnetic Wave Absorption”

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to “Covalent Bonding of MXene/Reduced Graphene Oxide Composites for Efficient Electromagnetic Wave Absorption”Fengxia YangFengxia YangMore by Fengxia Yang, Ying Huang*Ying HuangMore by Ying Huanghttps://orcid.org/0000-0001-5677-8426, Xiaopeng HanXiaopeng HanMore by Xiaopeng Han, Shuai ZhangShuai ZhangMore by Shuai Zhang, Meng YuMeng YuMore by Meng Yu, Junping ZhangJunping ZhangMore by Junping Zhang, and Xu SunXu SunMore by Xu SunCite this: ACS Appl. Nano Mater. 2023, 6, 10, 9070Publication Date (Web):May 4, 2023Publication History Received28 April 2023Published online4 May 2023Published inissue 26 May 2023https://doi.org/10.1021/acsanm.3c01907Copyright © 2023 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views131Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (801 KB) Get e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Construction of lychee-like MoS2 microspheres on rice husk-derived porous carbon for enhanced dielectric loss and efficient electromagnetic wave absorption

Construction of lychee-like MoS2 microspheres on rice husk-derived porous carbon for enhanced dielectric loss and efficient electromagnetic wave absorption

Two-Dimensional Metal Organic Framework derived Nitrogen-doped Graphene-like Carbon Nanomesh toward Efficient Electromagnetic Wave Absorption

Functional two-dimensional (2D) graphene-like carbon has the potential to be a good electromagnetic wave absorbing material due to its good electronic properties, but the preparation of 2D carbon via metal–organic frameworks (MOFs) derivation method is still a bottleneck. Herein, we fabricated ultrathin nitrogen-doped graphene-like carbon nanomesh (N-GN) via thermal exfoliation of 2D MOF (Zn-ZIF-L) directly. The species of the chloride salt that exfoliated Zn-ZIF-L have an effect on the nitrogen content, graphitization degree, pore size and specific surface area of N-GN. The Zn-ZIF-L derived N-GN exfoliated by KCl and LiCl simultaneously has the optimum reflection loss of −54 dB only with the thickness of 2.1 mm and the filler loading of 3 wt%. The excellent electromagnetic wave absorbing property is attributed to its favorable structure, micro-meso-macropores, N heteroatoms, abundant heterogeneous graphene-like carbon nanomesh interfaces and defects. Our simple and low-cost preparation process facilitates the large-scale production and application for electromagnetic wave absorbing material of functionalized graphene-like carbon.

N-doped carbon hollow spheres supported N-doped carbon nanotubes for efficient electromagnetic wave absorption

Hierarchical and hollow heteronanostructures had attached wide attention in electromagnetic wave (EMW) absorption fields due to their adjustable impedance matching and loss property. However, fabrication of well-defined heteronanomaterials with hierarchical and hollow features is challenging. Here, we develop a simple method to prepare N-doped carbon hollow spheres supported by N-doped carbon nanotubes (Ni@NCNT/NCHSs). Due to the hierarchical and hollow features, the Ni@NCNT/NCHSs exhibit high-efficiency EMW absorption performance. With a thickness only 1.6 mm, the optimized heteronanostructure has an RLmin of −64.75 dB and an EAB of 4.17 GHz. The experimental results demonstrate that the hierarchical and hollow heteronanostructures have significantly enhanced dielectric loss and conductive loss of the Ni@NCNT/NCHSs as well as the impedance matching characteristics, which are responsible for their enhanced EMW absorption performances. This work presents an effective method to synthesize hierarchical and hollow heteronanostructures for high-performance EMW absorption.

Multiple dimension-component designed Co/Co9S8/Ti3C2Tx MXene composite for enhanced microwave absorption

The two-dimensional (2D) transition metal carbide Ti3C2Tx MXene is a potential candidate for efficient electromagnetic wave absorbers due to its excellent intrinsic conductivity and structural machinability. However, Ti3C2Tx MXene also has some problems (such as self-stacking and single loss mechanism) that limit its practical electromagnetic wave absorption. Based on the electromagnetic wave absorption mechanism, electromagnetic responsiveness of absorbers can be modulated by designing the composition and structure. Herein, a 1D/2D Co/Co9S8/Ti3C2Tx composite has been synthesized by assembling 2D Ti3C2Tx MXene with the designed 1D magnetic structure. The 1D Co/Co9S8 was designed as a core-sheath structure that avoids magnetic agglomeration, and the assembly with 2D Ti3C2Tx sheets alleviates the self-stacking problem of Ti3C2Tx MXene sheets. More importantly, the magnetic component enriches the electromagnetic wave dissipation mechanism, and the multiple heterojunction surfaces provide strong polarization loss capability for the Ti3C2Tx MXene-based absorber. Benefiting from the unique structure and dielectric-magnetic synergistic loss, the Co/Co9S8/Ti3C2Tx composite shows an effective absorption bandwidth of 5.36 GHz (10.08–15.44 GHz) at 2.1 mm and the optimal RLmin value of −52.02 dB at 1.8 mm. This work provides an innovative idea for the design of effective Ti3C2Tx MXene-based absorbers.

Bimetallic MOF@bacterial cellulose derived carbon aerogel for efficient electromagnetic wave absorption

With bacterial cellulose (BC) as the skeleton, bimetallic CoZn-MOF (bi-MOF) was integrated into BC networks through an in situ growth approach. After carbonization at 600 °C, a highly porous, lightweight, conductive, compressible, and hydrophobic aerogel was obtained. Characterization results revealed that the MOF-derived magnetic Co/ZnO species are inlaid in the carbon matrix and dispersed uniformly. As-prepared composite aerogels were investigated for electromagnetic wave absorption. The optimized CZn-2 sample presented a total shielding effectiveness (SET) of 46.5 dB (X band, 8.2–12.4 GHz) at a thickness of 3 mm. The absorption shielding effectiveness (SEA) and the absorption proportion were determined to be 45.9 dB and 98.7%, respectively. The superior performance was attributed to the synergy of the conduction loss and magnetic loss, as well as the unique porous structure of aerogel. The hybrid aerogel also had an efficient electrothermal response, enabling its normal function in cold conditions. Moreover, the hybrid aerogel can be processed into a sensitive sensor for strain monitoring and displayed a high sensitivity for various human movements.

Architecture-inspired N-doped carbon nanotube bridging well-arranged MXene nanosheets toward efficient electromagnetic wave absorption

Multilayered Ti3C2Tx MXene, due to its tunable dielectric constants and structural designability, has been identified as rising star for exploring high-efficiency electromagnetic wave absorbers. However, it is still a huge challenge to address insufficient external contact of multilayered MXene at lower filler loading. Herein, inspired by the layer-pillar-layer architecture, a controllable catalytic-assisted nitrogen-doped carbon nanotubes bridging strategy is rationally proposed on the interlaminations of multilayered MXene units (MXene/TiO2/NCNTs, denoted as MTNC) to enhance dielectric dissipation ability. Through chemical vapor deposition, the NCNTs bridges as pillars not only break the confinement effect of multilayered MXene architecture like the process of seed germination but also effectively optimize impedance matching and increase dielectric constants. Simultaneously, the unique NCNTs-encapsulated magnetic components successfully prevents the agglomerations of CoNi nanoparticles and local mismatching problems, which facilitates the construction of three-dimensional magnetic coupling network. Specifically, the N heteroatoms and formed TiO2 species induce dielectric polarization and corresponding relaxation processes. Driven by unique layer-pillar-layer architecture, optimized impedance matching, and synergistic dielectric-magnetic dissipation capabilities, the resultant absorber delivers outstanding reflection loss value of −55.8 dB and broad absorption bandwidth of 5.88 GHz. This work provides a novel structural design strategy and enlightenment for developing high-performance multilayered MXene-based absorbers.

3D printing metamaterials for highly efficient electromagnetic wave absorption

Metamaterials (MMs) with artificial structures have extraordinary physical properties that cannot be found in traditional materials. MMs with electromagnetic wave absorption (MMAs) can be prepared through the structural design and arrangement of unit structures with special physical properties. These unit structures at the subwavelength scale are fundamental for MMAs to surpass the performance limits of bulk materials, so the matching of manufacturing processes is particularly important. The rapidly developing three-dimensional (3D) printing technology has shown great advantages and potential in manufacturing complex materials and structures, providing a simple, rapid, and efficient manufacturing method for researching and preparing MMAs. In this review, we introduce the concept and development of MMAs and focus on the research status of using 3D printing technology to manufacture MMAs. Furthermore, we briefly introduce their typical applications, discuss the inadequacies of the current development of MMs and the limitations of 3D printing technology in preparing MMAs, and propose the prospects for developing the combination of MMs and 3D printing.

Covalent Bonding of MXene/Reduced Graphene Oxide Composites for Efficient Electromagnetic Wave Absorption

Due to their high conductivity and unique surface chemical characteristics, MXene and reduced graphene oxide (rGO) have received a great deal of attention in the field of electromagnetic wave absorption (EMA). This study describes the covalent modification of rGO with amino-functionalized MXene to create an electromagnetic absorbent material called MXene-rGO composite. After amidation, an amide bond successfully assembles MXene and rGO. The absorber performs admirably when the mass ratio of MXene to rGO is 1:2 (sample MG-3). With a thickness of 2.7 mm, the best reflection loss (RL) is −47.98 dB at 6.4 GHz. Additionally, the best effective absorption bandwidth (EAB) (RL< −10 dB) is 4.08 GHz (11.84–15.92 GHz) with a 1.4 mm matching thickness. The performance of the EMA can be obtained by adjusting the dielectric parameters and the migration rate of the electrons using the covalent bond as a stable carrier channel. The high dielectric loss, superior impedance matching, and strong attenuation ability contribute to the great absorption performance.

High-entropy Pt18Ni26Fe15Co14Cu27 nanocrystalline crystals in situ grown on reduced graphene oxide with excellent electromagnetic absorption properties

The high entropy alloy is a powerful material due to its high hardness, strength, magnetic performance, corrosion resistance, and temperature stability. Moreover, when combined with reduced graphene oxide (rGO), it formed a novel material for electromagnetic (EM) absorption. In this work, monodisperse high entropy alloy nanocrystals combined with rGO to create a new type of high entropy alloy/rGO EM absorption material. A colloidal synthesis strategy was used to prepare high entropy Pt18Ni26Fe15Co14Cu27 nanocrystals with a small size of around 3.3 nm. These nanocrystals then in situ grew uniformly on the surface of rGO to form Pt18Ni26Fe15Co14Cu27/rGO nanocomposite, which were then characterized and tested for EM absorption performance. Compared to the pure high entropy Pt18Ni26Fe15Co14Cu27 nanocrystals, the composite exhibited an improved EM absorption performance with a minimum reflection loss of −41.8 dB at 4.9 GHz and efficient EM wave absorption up to a bandwidth of 2.5 GHz in the 9.4–11.9 GHz band. This novel high entropy alloy/rGO composite has great potential to be used as an excellent material for EM wave absorption.

Constructing 3D hierarchical CNTs/VO2 composite microspheres with superior electromagnetic absorption performance

To achieve efficient electromagnetic wave absorption (EWA) performance with requirements of low density and thin thickness, three-dimensional (3D) hierarchical CNTs/VO2 composite microsphere was successfully synthesized though an ultrasonic atomization process in this work. The phase composition, morphology, EWA performance and corresponding mechanism were investigated. The VO2 microspheres (MS) was obtained via the complete reduction of V2O5 by oxalic acid, and the introduced CNTs were uniformly distributed around VO2 MS. The addition of CNTs both improved the impedance matching and provided multiple attenuation modes. The highly conductive CNTs enhanced conductivity further increasing conductance loss. Moreover, heterogeneous interfaces formed between CNTs and VO2 phase generated strong polarization loss. Furthermore, the construction of 3D structure not only benefited the stability of structure but also extended the paths of EW reflection and scattering thus consuming more EW energy. With the synergistic effect of favorable impedance matching and attenuation ability, the excellent EWA performance was achieved that the minimum reflection loss was −58.2 dB with the effective absorption bandwidth of 3.94 GHz in X band. This research plays a significant guiding role in structural construction and optimization of EW absorber.

Fabrication of a flexible and efficient electromagnetic wave absorber based on reduced graphene oxide/Fe7Co3 filled into polydimethylsiloxane

A flexible and efficient reduced graphene oxide/Fe7Co3/polydimethylsiloxane (rGO/Fe7Co3/PDMS) composite electromagnetic wave (EMW) absorber was prepared by a fast and simple liquid reduction and subsequent liquid phase blend method. The introduction of rGO tunes the dielectric constant and dielectric loss of the composite absorber, and Fe7Co3 imparts magnetic loss characteristics to the material. The rheological properties of PDMS enable rGO/Fe7Co3 to be well dispersed within it, forming a homogeneous structure, which contributes to the synergistic effect of the components and improves the impedance matching conditions and attenuation capability of the composite absorber. It is worth noting that the EMW absorption properties of the composites can be effectively adjusted by changing the amount of rGO/Fe7Co3 added to the PDMS. When the amount of rGO/Fe7Co3 is 8.00 wt%, rGO/Fe7Co3/PDMS-8 shows superior EMW absorption property. The minimum reflection loss (RLmin) of − 52.58 dB at 1.80 mm, and the widest effective absorption bandwidth (EAB, RL≤−10 dB) can reach 6.40 GHz (11.40–18.00 GHz) at only 1.60 mm. Furthermore, the twist test shows that the RLmin and widest EAB of rGO/Fe7Co3/PDMS-8 remained at 92.64 % and 97.50 % of its initial values after 1500 twists, respectively, demonstrating its excellent flexibility. These results indicate that such rGO/Fe7Co3/PDMS-8 composite is very promising as a next generation flexible and efficient EMW absorbing material.

Efficient electromagnetic wave absorption and Joule heating via ultra-light carbon composite aerogels derived from bimetal-organic frameworks

Lightweight carbon-based aerogels with fast heat dissipation capability are promising electromagnetic wave absorber materials for developing integrated electronics, artificial intelligence, and human-interaction equipment under harsh thermal environments. Herein, the bimetallic (cobalt (Co) and nickel (Ni)) metal–organic frameworks (CoNi-MOFs), cellulose nanofibrils (CNFs), and aramid nanofibers (ANFs) were assembled into a conductive and magnetic CoNi@carbon/ANF/CNF carbon composite aerogel (CoNi@C/ACA) with an ultra-low density of 6.15 mg/cm3 using freeze-drying and subsequent carbonization treatment. Owing to the synergistic effects of multiple reflections inside the three-dimensional interconnected structures, abundant interfacial/dipolar polarizations, and coordinated dielectric and magnetic losses, the CoNi@C/ACA achieved a fascinating minimum reflection loss value of −66.57 dB and broad effective absorption bandwidth up to 6.3 GHz, which were characterized with an ultra-low loading of 1.8 wt%. In addition, it displayed good thermal stability with a super-fast Joule heating (cooling) rate at low driving voltages. These unique characteristics of the ultra-light CoNi@C/ACA make it a promising material for demanding applications, e.g., electromagnetic pollution elimination and thermal management.

A novel synthesis of Porous Fe4N/carbon hollow microspheres for thin and efficient electromagnetic wave absorbers

Modulating the structure and morphology is essential in fabricating high-performance electromagnetic absorbing materials. Herein, we obtained porous Fe3O4/carbon hollow microspheres and porous Fe4N/carbon hollow microspheres derived from Fe-glycerol hollow microspheres. Through structure and morphology analysis, we proved the existence of porous and hollow features. By comparison, it can be found that the porous Fe4N/carbon hollow microspheres have electromagnetic wave absorption performance superior to that of porous Fe3O4/carbon hollow microspheres. The reflection loss value of porous Fe4N/carbon hollow microspheres reaches −42.2 dB at a matching thickness of merely 1.4 mm, and its effective absorbing bandwidth approaches 4.5 GHz, whereas the reflection loss of porous Fe3O4/carbon hollow microspheres in the 2–18 GHz range is over −10 dB. Reasons for the better electromagnetic wave absorption performance are revealed to be that the magnetic Fe4N has higher complex permittivity and complex permeability, and the porous hollow microspherical structure increases the multiple scattering and reflection of electromagnetic waves. Meanwhile, the impedance matching and attenuation constant are optimized together through the synergy of dielectric and magnetic loss. This research can provide instructive findings for thin-thickness electromagnetic wave absorbing materials based on Fe4N with an appropriate microstructure.